In recent years the capacity demand of mobile data traffic has increased considerably. To this extent, cellular network sharing is a key building block for virtualizing mobile networks in order to handle the explosive capacity demand of the mobile traffic and to reduce the CAPEX (Capital Expenditure) and OPEX (Operational Expenditure) burden faced by operators to handle this demand.
3GPP (3rd Generation Partnership Project) has recognized the importance of supporting network sharing since 3GPP TR 22.951: Technical Specification Group Services and System Aspects; Service aspects and requirements for network sharing (Release 6), March 2003 and defined a set of architectural requirements and technical specifications which have been updated until 3GPP TS 22.951: Technical Specification Group Services and System Aspects; Service aspects and requirements for network sharing (Release 10), March 2011 and 3GPP TS 23.251: Technical Specification Group Services and System Aspects; Service aspects and requirements for network sharing (Release 11), September 2011 respectively.
The standardized network sharing functionality of recent times has been sufficient to cover mobile operators' basic requirements in the past. However, as operators look for new ways to reduce costs due to their increasing financial investment burden, new business models for operators and infrastructure owners are emerging, calling for more flexibility and to extend existing standardized network sharing functionality.
The 3GPP RAN Sharing Enhancements (RSE) Study Item of the System Architecture Working Group 1 (SA1) is defining new scenarios in which multiple operators may share radio access network resources, which is described in 3GPP TR 22.852, “Study on RAN Sharing Enhancements”, Release 14, August 2012. The RSE Study Item creates potential requirements that complement existing 3GPP system capabilities for sharing common radio access network resources. In this context of radio access network sharing 3GPP TR 22.852 establishes the following definitions:                hosting RAN: radio access network resources, in particular E-UTRAN resources, provided by a hosting RAN provider for use by a participating operator;        hosting RAN provider: A provider of a hosting RAN;        participating operator: operator that uses allocated shared radio access network resources provided by a Hosting RAN provider under agreement;        requesting operator: operator that requests the use of unallocated shared radio access network resources provided by a hosting RAN provider under agreement.        
Generally, radio access network sharing may make use of the concept of resource pooling which is used in different application areas. For instance, it is referred to Wischik et al. “The resource pooling principle”, ACM SIGCOMM Computer Communication Review, Volume 38, Issue 5, Pages 47-52, October 2008 or the resource pooling system and method in communication systems described in U.S. Pat. No. 6,195,362 B1.
Furthermore, it is exemplarily referred to the references US 2011/0124332 A1 and US 2001/0012778 A1 which describe handover mechanism for regular load balancing purposes.
However, the radio access network resources of mobile networks are consumed by mobile terminals that are subject to constraints such as Quality of Service (QoS) requirements, economic limits, etc. Furthermore, in mobile networks there are side-conditions such as independent and unpredictable movement of mobile users, radio signal level changes, etc. Therefore, there is a need for improved adaptations and further developments in order to satisfy and overcome the characteristics of mobile networks.